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MAN IN THE MODERN WORLD
invents a ruse, and acts its part with consummate skill to draw the
intruder away. All the evidence, however, points to (his too being
merely instinctive, a trick not invented by the individual bird, but
patented by the species. If it were the fruit of intelligent reflection,
we should expect to find some individuals of a species practising it,
others not, and great variations in the dlicticy of the performance;
but in species like the purple sandpiper or the arctic skua, every
individual seems to be a good performer, and this without any
previous training. The trick, in fact, is on a par with the purely
automatic "shamming dead" which many insects practise: it is the
inevitable outcome of the animal's nervous machinery when this
machinery is stimulated in a particular way.
Besides instinctive actions, we could multiply instances of unin-
telligent behaviour among birds. If a strange egg is put among a
bird's own eggs, the mother may accept it through uncritical instinct,
or may intelligently turn it out of the nest and continue to sit. But a
quite common reaction 3s for it to turn the strange egg out, and then to
desert its nest—a most decidedly illogical procedure! Again, Mr. St.
Quentin had two hens and one cock of a kind of sand-grouse in his
aviary. This is a bird in which the hens normally sit by day, the cock
by night. One year, both the hens laid at the saint1: time*. The cock
tried his best, sitting part of the night on one clutch, part on another,
but of course the eggs came to nothing. If the birds had had any
intelligence, they would have divided up the twenty-four hours so
that the eggs were always brooded; but the day-brooding of the hens
and the night-brooding of the cock arc mechanical instincts, and
intelligence neither enters into them in normal nor modifies them in
abnormal circumstances.
But because birds are mainly instinctive and not intelligent in their
actions, it does not follow that their minds are lacking in intensity or
variety: so far as we can judge, they must be experiencing a wide
range of powerful emotions.
A bird clearly finds an intense satisfaction in fulfilling its brooding
impulse or the impulse to feed its young, even though the impulse
may be, for want of intelligence, what we should call a strangely blind
one: and when the young birds are threatened with clanger, the
parents clearly are suffering very real distress, just as birds suffer very
real fear when cornered by an enemy. In song, too, the bird, besides
expressing a certain general well-being, is giving vent to a deep current
of feeling, even if it does not understand the feeling or reflect upon it,
as would a human poet or musician. For the moment, they are that
feeling. Some birds are so obsessed by their emotions during their
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